"Peptides" are having a moment. You'll hear the word on skincare shelves, on wellness podcasts and in some very questionable corners of TikTok. They are not all the same thing. Here's a clear guide to the peptides that belong in your skincare routine, what they can realistically do, and what to skip.
What is a peptide?
A peptide is a short chain of amino acids, the building blocks of proteins like collagen. In skincare, peptides are added to serums, creams and eye products to support skin that looks smoother, firmer and more elastic. Think of them as helpful messengers in your routine, not magic.
The 3 types you'll see on labels
1. Signal peptides
These are the most researched. Palmitoyl pentapeptide-4 (often sold as Matrixyl) has the strongest topical evidence, with a split-face study showing reduced wrinkle depth over 8 weeks. You'll also see palmitoyl tripeptide-1 and -38 (Matrixyl 3000).
2. Carrier peptides
The famous one is copper peptide (GHK-Cu), listed on labels as Copper Tripeptide-1 and studied since the 1970s. Topical studies report improvements in how firm and smooth skin looks. It's a great fit for a night routine.
3. "Expression line" peptides
Argireline (acetyl hexapeptide-8, also listed as acetyl hexapeptide-3) is popular in eye creams and serums. Studies show modest smoothing of expression lines. It's a nice extra, but dermatologists are clear it is not a substitute for injectables.
What peptides can't do (the honest part)
- Results are gradual. Most studies run 4 to 12 weeks. Consistency matters more than any single product.
- Not every formula tells you the dose. Many products don't list concentrations, so think of peptides as a supporting player alongside SPF, hydration and a retinoid.
- Topical peptides are not the same as injectable "peptides." The injectable peptides you may see promoted online for "longevity" or recovery (like BPC-157 or TB-500) are a completely different category. A 2026 dermatology review in Healio notes that evidence for them is mostly from animal studies or anecdotes, with no approved human use. We don't sell them and don't recommend them.
GHK-Cu: your copper peptide questions, answered
What is GHK-Cu?
GHK-Cu is a small copper peptide that occurs naturally in the body. On a skincare label it usually appears as Copper Tripeptide-1. It has been researched since the 1970s, and topical studies report skin that looks firmer, smoother and less lined over time.
Is GHK-Cu skincare the same as GHK-Cu injections?
No. Serums, creams and masks with copper peptides are cosmetics that work on the surface of your skin. The injectable GHK-Cu sold online as a "research peptide" is a different thing entirely. A 2026 dermatology review in Healio found no solid human evidence for injecting it for skin or anti-aging, and safe doses haven't been established. We don't sell injectables and don't recommend them; if you're curious, talk to your doctor.
How do I use a copper peptide product?
Apply it after cleansing and toning, before your moisturizer, or use a cream or eye cream that already contains it. Evenings are an easy fit. It layers well with hyaluronic acid, ceramides and niacinamide. To keep things simple, use vitamin C in the morning and copper peptides at night. Patch test anything new first.
Which Glasswell products contain GHK-Cu?
Several of our K-beauty favorites list Copper Tripeptide-1, including the medicube Deep Lifting Peptide Eye Cream, the COSRX Advanced Snail Peptide Eye Cream and the medicube PDRN Pink Hyaluronic Moisturizing Cream. See them all in our Copper Peptide (GHK-Cu) edit.
How to add peptides to your routine
- Cleanse gently.
- Toner or essence for hydration.
- Peptide serum on damp skin, morning or night.
- Moisturizer, ideally with ceramides, to seal it in.
- SPF 30+ every morning. Sun protection protects the results you're working for.
Peptides play well with most ingredients, including hyaluronic acid, ceramides, niacinamide and retinol, which makes them an easy first "firming" step for sensitive or dry skin. You'll often see them paired with PDRN in K-beauty formulas. Curious about that one? Read What Is PDRN?
Our K-beauty peptide picks
medicube PDRN Pink Peptide Serum
medicube Deep Lifting Peptide Eye Cream
COSRX Peptide Collagen Hydrogel Mask
COSRX Snail Peptide Eye Cream
- MEDICUBE PDRN Pink Peptide Serum: a lightweight daily serum for bouncy, glassy-looking skin.
- medicube Deep Lifting Peptide Eye Cream: peptides, collagen and copper for the delicate eye area.
- COSRX The Peptide Collagen Lifting Glow Hydrogel Mask: a weekly treat for plumper-looking skin.
- COSRX Advanced Snail Peptide Eye Cream: hydrating and gentle.
Shop the full Collagen & Peptides edit, or build a long-game routine with our Skin Longevity picks.
Ready to try peptides? Shop the medicube PDRN Pink Peptide Serum, or take our 5-question skin quiz to see where it fits in your routine.